The US ambassador gets a tongue-lashing from Brazilian officials angry about NSA eavesdropping on their president, and Obama is likely to get an earful from spied-upon Europeans later this week at the G20 summit. One problem for the US: It doesn't know how much more will be leaked.

On Monday the Brazilian government reacted angrily to new reports that the NSA intercepted the communications of President Dilma Rousseff and her top aides. Brazil’s Foreign Ministry summoned US Ambassador Thomas Shannon for a dressing-down, and told him to provide a “prompt written explanation” of the allegations, according to The Associated Press.

Brazil learned of the alleged eavesdropping in a Sunday night show on Globo TV, which cited 2012 documents from Mr. Snowden as its source. In response, officials called for some kind of international effort to produce regulations guarding against future electronic intrusions.

According to the AP, Brazilian Foreign Minister Luiz Alberto Figueiredo said, “We’re going to talk with our partners, including developed and developing nations, to evaluate how they protect themselves and to see what joint measures could be taken in the face of this grave situation.”

The NSA also intercepted e-mails, text messages, and phone calls from Mexican President Enrique Peña Nieto, said the Globo TV report. The Mexican government said it had complained through official channels.

If nothing else, the latest tranche of Snowden revelations shows that the NSA leaker’s information is not tapped out. Big stories based on his documents continue to appear, including last week’s Washington Post exposé on the details of the current US "black budget" for intelligence agencies.

On Sept. 2 the Post published another long piece based on Snowden-provided material, detailing how much Washington distrusts and spies upon Pakistan.

More NSA scoops are undoubtedly coming. Both The New York Times and the independent US investigative journalist group ProPublica have obtained Snowden-leaked documents, according to news reports.

Last week, the British government asked the Times to destroy documents related to the operations of the NSA and the British eavesdropping agency Government Communications Headquarters, according to Reuters. The US paper did not reply to the request.

The US intelligence community may still be unable to determine exactly how much classified information Snowden has, meaning US officials have little idea when Snowden’s leaks might end. NBC News reported last week that the British government has told a court hearing that David Miranda, the partner of journalist and Snowden collaborator Glenn Greenwald, had 58,000 classified documents in his possession when he was detained and searched at London's Heathrow Airport on Aug. 18.

Mr. Greenwald has previously said that Snowden downloaded about 20,000 documents.

The furor in Brazil over eavesdropping also shows that Snowden-provided NSA revelations will continue to affect US international relations for some time to come, even as the US is seeking international support for a possible intervention in Syria.

President Obama’s upcoming trip to Russia for an economy-focused Group of 20 summit has already been scrambled. Mr. Obama called off a scheduled one-on-one with Russia’s Vladimir Putin after Snowden obtained temporary asylum in Russia. European leaders upset about NSA activities will surely give Obama an earful.

Some US critics of Snowden’s activities say American spying on Brazil shouldn’t be surprising. Foreign espionage is the NSA’s job, after all.

Furthermore, leaking details of such spying isn’t whistle-blowing, because it doesn’t deal with allegations that the NSA has overreached in domestic surveillance, according to right-leaning talk host Ed Morrissey.

“What Snowden is doing with these revelations is explicitly intended to damage the US and its ability to conduct intelligence outside of its borders, not to push a much-needed debate on the PATRIOT Act and checks on domestic surveillance after 12 years,” writes Mr. Morrissey at "Hot Air."

Greenwald rejects this notion. He tweeted on Tuesday that people should read Snowden’s words in acceptance of a German whistle-blower award and judge whether he is a “traitor ... rather than a whistleblower.”

In accepting the award in absentia, Snowden said, “the greater reward and recognition belongs to the individuals and organizations in countless countries around the world who shattered boundaries of language and geography to stand together in defense of the public right to know and the value of our privacy.”